Discovered zinc eluted from glassware inhibits the embryo development: Leading to development of safer and more effective IVF

Kindai University

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Glassware used in in vitro fertilization; syringe filter, glass-bottom dish, glass pipette, etc. (left)
Embryo developmental arrest caused by the glass wares, not by plastic (right)

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Credit: Kazuo Yamagata, Kindai University, Japan

1. Overview

The research team discovered that glassware used to manipulate and culture fertilized eggs in the fields of assisted reproductive technology (ART), livestock farming, and basic research contains toxic substances that interfere with the development of fertilized eggs (embryos). The team also identified the toxic substance as zinc, and developed a method to counter it by closely analyzing its effects on mouse, cow, and human fertilized eggs. The results of this research suggest that the unknown cause of reduced IVF outcomes might be due to the toxicity of glassware. It is hoped that this will lead to the development of safer and more effective IVF methods in the future. The researchers participating in this research include: Kazuo Yamagata (Professor, Graduate School of Biology-Oriented Science and Technology, Kindai University), Tatsuma Yao (Senior Researcher, Research and Development Center, Fuso Pharmaceutical Industries, Ltd.), Kazuki Kurimoto (Professor, Department of Embryology, Nara Medical University), Akira Funabashi (Professor, Department of Biosciences and Informatics, Keio University), Mikiko Tokoro (Researcher, Asada Institute for Reproductive Medicine, Asada Ladies Clinic), Satoshi Sugimura (Professor, Department of Biological Production, Tokyo University of Agriculture and Technology), and Takuya Yamamoto (Professor, Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University).

 

2. Key Points

・Discovered that some glassware used in in vitro fertilization (IVF) inhibits the development of fertilized eggs.
・Identified that the toxic substance that inhibits development of fertilized eggs was “zinc” eluted from glassware.
・The findings of this study leads to the development of safer and more effective in vitro fertilization (IVF) methods.

 

3. Research Background

In the field of assisted reproductive technology (ART), livestock farming, academic basic research, in vitro fertilization (IVF) is performed in which eggs and sperm are removed from the body, fertilized and developed in culture medium, and then the fertilized eggs are transferred to the uterus. In the nearly 50 years since the first IVF baby was born in 1978, many technological developments have been made in fertilization methods, culture media, and other areas to improve the development rate of fertilized eggs and pregnancy rates. As a result of these technological developments, the birth rate in ART has risen significantly from around 5% in 1980 to around 30% today. In order to further increase the birth rate, it is necessary to improve the environment in which embryos are cultured. Many glass instruments are used in IVF operations. For example, glass-bottom dishes, which have a thin glass bottom that allows high-resolution observation of the embryos, are used as culture dishes. Filters containing glass fibers are used to remove impurities and bacteria from the culture medium, and thin glass pipettes are also used to manipulate the embryos. In addition to these, micropipettes used in intracytoplasmic sperm injection (ICSI) procedures and some containers for culture medium are also made of glass.

In previous research, the team developed a live-cell imaging technique to continuously observe the developmental process of embryos over a long period of time. This technique makes it possible to use large amounts of image data to numerically detect subtle differences in embryo development. During the course of the experiments, the team noticed that in some cases, the embryo development rate unexpectedly declines, even though multiple experimental conditions were kept consistent. After investigating the reason for this, the team found that the declines were caused by the glass-bottom dishes used for culture, and began their research based on the hypothesis that laboratory equipment, especially glassware, might contain some kind of toxicity that inhibits embryo development.

 

4. Content

The research team discovered that some of the glassware had leaked toxic substances that inhibited embryo development, and after analyzing the substances, the team found that the toxic substance was zinc. Zinc induced delayed development in mouse embryos, abnormal chromosome segregation, abnormal cytokinesis, and abnormal zygotic gene activation, and significantly reduced the formation of blastocysts.

Post-implantation, zinc-exposed embryos were associated with similar birth rates to embryos cultured without zinc, however, the birth weight increased by an average of 18%. Furthermore, zinc exposure affected the development of bovine and human embryos, with species-based variation in the strength of these effects. As a result of investigating ways to reduce the embryotoxic effects of zinc, the research team found: The embryo development rate and birth rate do not decrease in culture medium that had come into contact with glass, by adding chelating agent EDTA (ethylenediaminetetraacetic acid) to the culture medium at the appropriate time and concentration, or by thoroughly cleaning the glassware beforehand. This research highlights the importance of careful management of the equipment used in embryo culture, and also is expected to lead to the development of safer and more effective in vitro fertilization methods.

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Journal

Biology of Reproduction

DOI

10.1093/biolre/ioaf050 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Zinc eluted from glassware is a risk factor for embryo development in human and animal assisted reproduction

 

Douglas-fir in Europe: Climate savior or biodiversity threat?

Tsinghua University Press

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Impact of Douglas fir on above- and below-ground biodiversity through changes in abiotic (left) and biotic factors (right)

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Credit: Marlene Graf, Rafael Achury, Isabelle Lanzrein, Ronja Wenglein, Peter Annighöfer, Stefan Scheu, Wolfgang W. Weiss

As climate change pushes Europe’s native forests to their limits, the North American Douglas-fir (Pseudotsuga menziesii) is emerging as a potential climate-resilient candidate. But could this fast-growing newcomer harm local ecosystems? A sweeping new study recently published in Forest Ecosystems reveals unexpected answers.

Researchers from Technical University of Munich, University of Göttingen, and Centre of Biodiversity and Sustainable Land Use analyzed decades of data from across Europe, examining how Douglas-fir introduction affects biodiversity compared to native trees like spruce and beech. The results challenge common assumptions: in 78.6% of cases, Douglas-fir showed no significant impact on local species. Positive effects were rare (just 12% of observations), while negative impacts were even scarcer (only 9%).

The findings varied by species and habitat. Canopy spiders thrived in Douglas-fir’s dense branches, while arthropod diversity is reduced due to the distinct bark structure. Birds faced mixed fortunes—some species found less food in Douglas-fir stands during winter, but mixed forests softened these effects. Soil organisms and fungi showed more complex responses, often tied to subtle changes in leaf litter and soil chemistry.

The key takeaway? Context matters. Pure Douglas-fir plantations sometimes altered ecosystems, but mixing them with native trees minimized disruptions. The study highlights important unknowns too, like impacts on bats and long-term soil health.

For forest managers, the message is clear: thoughtful integration beats wholesale replacement. Based on the limited studies retrieved by the review, it is reported that Douglas-fir inclusion has non-significant or neutral effects. The team calls for more studies to pinpoint safe thresholds for its use, ensuring this imported tree helps rather than harms Europe’s struggling woodlands.

Funding: This study was supported by grant klifW018 of the Bavarian State Ministry for Food, Agriculture and Forestry for funding.

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Journal

Forest Ecosystems

DOI

10.1016/j.fecs.2025.100319 

Article Title

The effect of Douglas-fir on biodiversity in European forests – What do we know and what do we not know?

 

Focus on sanitation and clean water may improve control of endemic cholera

Pathogens that persist in hosts and environments may require tailored management strategies, according to new study of endemic cholera interventions in Sub-Saharan Africa

Penn State

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UNIVERSITY PARK, Pa. — Public health strategies, from vaccination to improving sanitary conditions, may have different impacts depending on whether a disease is endemic — persisting in a particular location for an extended period of time — or a new outbreak, because the dominant transmission routes may differ, according to a new study. The study, which modeled cholera transmission after interventions in the Democratic Republic of the Congo (DRC), highlights how long-term strategies like improving access to clean water and sanitary infrastructure could be particularly effective in locations where cholera is endemic due to the contribution of an environmental reservoir.

A paper describing the research, led by researchers at Penn State, was published in the journal PLOS Neglected Tropical Diseases. 

“When conducting interventions for an infectious disease, public health officials must decide how to allocate resources and prioritize strategies that will have the most impact,” said Alexandre Blake, first author of the paper, who completed the work when he was a postdoctoral researcher in biology in the Penn State Eberly College of Science and the Center for Infectious Disease Dynamics (CIDD). “We are particularly interested in how to allocate resources in endemic situations. If an epidemic is like a forest fire, with transmission burning intensely before coming to a stop, then an endemic disease is more like a slow burn, with transmission constantly in the background with occasional flare ups. We used statistical modeling to better understand cholera transmission in the city of Kalemie in the DRC, where it is endemic. We specifically focused on the two years following a series of interventions to evaluate the impact of those interventions.”

Cholera is bacterial disease that can be transmitted when the bacteria are ingested. The disease can cause severe diarrhea, which can potentially contaminate water sources with the disease-causing bacteria and lead to increased transmission, especially in areas with poor sanitation or limited infrastructure to treat drinking water. Although many people who become infected have no symptoms or mild symptoms, symptomatic cases of cholera can progress quickly, leading to severe dehydration that can be fatal. One study estimated that 1.3 to 4 million cholera cases worldwide cause between 21,000 and 143,000 deaths each year. The Global Task Force on Cholera Control has created a road map to eliminate cholera in 20 countries by 2030, particularly targeting sub-Saharan Africa, where cholera has been endemic since the early 1970s. 

Interventions for cholera often include vaccination, which can be rapidly implemented, as well as water, sanitation and hygiene improvements, collectively called WASH. Large scale WASH strategies, such as improving infrastructure for sanitation and access to clean water, are more expensive and take months to years to implement.

“We know that WASH and vaccination are great tools to prevent cholera,” Blake said. “But the impact of vaccination has largely been studied in epidemic situations as a rapid response. WASH is slow and costly to implement which makes it hard to accomplish in low-income settings. To eliminate cholera, we need to better understand the many factors that drive transmission as well as the impact of different interventions in endemic settings.”

From late 2013 to early 2016, Doctors Without Borders led intervention efforts in Kalemie, including vaccination and WASH efforts. WASH efforts focused on improving access to clean water, for example by installing pipes, water reservoirs and public drinking fountains, as well as distributing water filters and, during outbreaks, chlorinating drinking water to kill bacteria. 

The researchers built several statistical models to determine which combination of factors best explained cholera transmission during this period. They used satellite images of light at night to track seasonal occupancy of the city, which impacts the number of people in the area capable of becoming infected with or transmitting the bacteria. They also included rainfall and other environmental variables that might impact the bacteria’s ability to survive in the nearby lake and infect more people.

Although the researchers did not find much impact of the seasonal movement of people in Kalemie, they did find that a large portion of transmission resulted from the environment, likely because the lake acts as a reservoir for the cholera bacteria.

“Because the bacteria persist in the lake, some residents of the city may have opportunities to be regularly exposed and may ultimately develop some level of immunity, which shapes transmission dynamics and eventually the impact of some interventions,” Blake said.

The researchers estimated that most of cholera transmission could be avoided if environmental exposure or contamination was prevented. The researchers also estimated that the majority of residents had some immunity during this period due to regular outbreaks and persistent exposure in the environment. Taken together, the researchers said that vaccination would have a smaller impact on preventing transmission compared to WASH in such settings.

Blake said that early in epidemic situations, most people in the area are assumed not to be immune to the disease, so fast-paced responses like vaccination can be a good choice for management — but endemic infections require a more comprehensive approach. 

“In an epidemic setting, it’s almost never a wrong decision to vaccinate because the majority of the population is susceptible to the disease, so vaccinating early in the outbreak can quickly increase immunity levels,” he said. “But in endemic settings, this assumption may not be true. Vaccines are ideal for people who do not already have some level of protection from previous exposure, but testing to see if an individual is already immune can be costly or impractical. So, in areas like Kalemie where there may be relatively high levels of immunity due to environmental transmission, we estimate a higher proportion of cases avoided from long-term strategies like WASH if both strategies are competing because of limited resources.”

An additional benefit of WASH, Blake said, is its positive impact on general health. 

“Whether it’s talking to people on the street about hygiene or improving sanitation and access to clean water, WASH provides basic needs and can reduce transmission of more than just cholera,” he said. “WASH efforts have greater up-front costs but have long-lasting impacts.”

Blake noted that studies to confirm the level of immunity in Kalemie and other endemic areas are needed. Ultimately, he said, this information could be used to refine intervention strategies targeting endemic diseases that have an environmental reservoir that contributes to transmission.

“Vaccination and WASH efforts are both critical tools in controlling the spread of diseases like cholera,” said Nita Bharti, associate professor of biology who is also affiliated with CIDD at Penn State and senior author of the paper. “But a ‘one size fits all’ approach is not going to work across epidemic and endemic situations. We need a location-specific understanding of the role of the environment and transmission routes to control cholera and other infectious diseases in endemic areas.”

In addition to Blake and Bharti, the research team at Penn State includes Adam Walder, who has since graduated with a doctoral degree in statistics, and Ephraim Hanks, associate professor of statistics, both affiliated with CIDD. The team also includes Placide Okitayemba Welo at Programme National d’Elimination du Choléra et de lutte contre les autres Maladies Diarrhéiques in the DRC; Francisco Luquero at Epicentre in France; and Didier Bompangue at the University of Kinshasa in the DRC. 

Funding from the U.S. National Institutes of Health, U.S. National Science Foundation and the U.S. National Institute of Food and Agriculture supported this research.

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Journal

PLOS Neglected Tropical Diseases

DOI

10.1371/journal.pntd.0012867 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Impact of a multi-pronged cholera intervention in an endemic setting

 

Legalizing youth-friendly cannabis edibles and extracts and adolescent cannabis use

JAMA Network Open

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About The Study:

 In this serial cross-sectional study of adolescents in grades 7 to 11, legalization of cannabis edibles and extracts was associated with an increase not only in edible cannabis use and cannabis smoking, but also in the overall prevalence of cannabis use and co-use of alcohol and cannabis, highlighting the need for stricter policy measures to curb adolescents’ access to cannabis edibles and extracts and greater awareness among adolescents about harms of cannabis use.

Corresponding Author: To contact the corresponding author, Hai V. Nguyen, PhD, email hvnguyen@mun.ca.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2025.5819)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time https://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2025.5819?guestAccessKey=c0957767-f5eb-4d6d-88a4-15c747418b57&utm_source=for_the_media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=041825

About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication. 

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Journal

JAMA Network Open

 

Colder temperatures increase gastroenteritis risk in Rohingya refugee camps

Hokkaido University

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Kutupalong refugee camp in Cox’s Bazar, Bangladesh. (Photo: Takuya Takata)

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Credit: Takuya Takata

Colder temperatures are linked with increased risk of diarrhea among Rohingya refugees in Bangladesh, emphasizing the need for climate-sensitive health strategies in refugee settings.

A new study by scientists at Hokkaido University has found that lower temperatures significantly increase the risk of gastroenteritis among Rohingya refugees living in Bangladesh’s Kutupalong and Nayapara camps. Gastroenteritis is a viral or bacterial infection that causes inflammation of the stomach and intestines, resulting in diarrhoea, vomiting, and stomach pain. Published in JAMA Network Open, the study is the first to explore how temperature affects stomach illnesses in displaced populations, emphasizing the need for better climate-related health strategies to protect these vulnerable communities.

The Rohingya are among the largest stateless populations in the world, accounting for one-seventh of the global stateless population. Bangladesh has hosted several waves of Rohingya refugees since 1948, with a significant increase in 2021 due to escalating unrest in Myanmar. Today, an estimated 918,898 Rohingya live in 34 camps in Cox’s Bazar, Bangladesh. These camps are overcrowded, with populations reaching up to 60,000 people per square kilometer, which creates severe public health challenges. Infectious diseases, such as respiratory infections, viral fever, and diarrhea, are widespread due to unsanitary conditions, reliance on contaminated shallow wells, and limited access to clean water, particularly during the dry season.

The study, which analyzed data from over 64,000 cases of gastroenteritis recorded in UNHCR-run clinics between 2019 and 2021, revealed a link between temperature changes and gastroenteritis risk. In Kutupalong, researchers found that the risk increased when temperatures either dropped or increased beyond the reference temperature of 26°C. This suggests that both extreme cold and extreme heat contribute to a higher number of gastroenteritis cases. In Nayapara, as temperatures fell, the risk of gastroenteritis steadily increased, with no clear threshold or turning point.

A key finding of the study was that colder weather tended to have a delayed effect, with the peak number of gastroenteritis cases occurring about two and a half weeks (around 18 days) after exposure to cold temperatures. This delayed effect was consistent in both camps.

"Research has shown that viral gastroenteritis, such as that caused by norovirus and rotavirus, are more common in colder weather and can last for up to two weeks. In contrast, warmer temperatures create favourable conditions for bacterial infections like Salmonella and Campylobacter, which typically cause illness for a few days to a week," explains Associate Professor Xerxes Seposo of the Department of Hygiene, Graduate School of Medicine at Hokkaido University, the study’s corresponding author and joint first author. "Our study highlights how cold weather can drive the spread of gastroenteritis in refugee camps, where poor sanitation and limited access to clean water make infections even more difficult to control."

The study emphasizes the growing threat that climate change poses to global health, especially for refugee populations. As population displacement rises, understanding how weather impacts disease risks in these displaced populations (i.e. refugee camps) becomes increasingly important.  “While it is important to acknowledge the documented health risks faced by these vulnerable populations, greater emphasis and action are needed to strengthen the climate resilience of their healthcare systems,” said Takuya Takata of the Department of Hygiene at Hokkaido University, the study’s other joint first author.

This study offers important insights into the health challenges posed by climate change. “As the Rohingya refugee population is expected to continue growing, policymakers and humanitarian organizations must act quickly to ensure these communities receive the support and resources necessary to adapt to the unpredictable effects of climate change,” Seposo concludes.

Gastroenteritis risk (top) curves by temperature in Kutupalong (left) and Nayapara camps (right), Cox’s Bazar, Bangladesh. In Kutupalong, the risk is lowest at 26°C, while in Nayapara, the risk decreases as the temperature rises. (Takuya Takata, Xerxes Seposo, et al. JAMA Network Open. April 18, 2025)

Credit

Takuya Takata, Xerxes Seposo, et al. JAMA Network Open. April 18, 2025

Clockwise from top left: Takuya Takata, Xerxes Seposo, Nasif Hossain, Kayo Ueda, authors of the study. (Photos provided by Xerxes Seposo)

Credit

Xerxes Seposo

Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2025.5768 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Air Temperature and Gastroenteritis Among Rohingya Populations in Bangladesh Refugee Camps

Article Publication Date

18-Apr-2025

 

Lehigh University water scientist Arup K. SenGupta honored with ASCE Freese Award and Lecture

He will virtually present May 21 on “Development and Global Application of Hybrid Ion Exchange Processes in Sustainable Water Treatment: From Decontamination to Desalination” during the 2025 World Environmental & Water Resources Congress

Lehigh University

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Arup K. SenGupta, senior research scientist and professor emeritus of civil and environmental engineering in Lehigh University's P.C. Rossin College of Engineering and Applied Science, has received the 2025 Simon W. Freese Award for his pioneering contributions to ion exchange science and sustainable water treatment.

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Credit: Christa Neu/Lehigh University

Lehigh University Senior Research Scientist Arup K. SenGupta, a professor emeritus in the Department of Civil and Environmental Engineering, is the 2025 recipient of the Simon W. Freese Environmental Engineering Award and Lecture, presented by the American Society of Civil Engineers (ASCE).

SenGupta, an ASCE Fellow, is an internationally recognized water scientist whose research has led to sustainable solutions for removing arsenic, fluoride, and other contaminants from drinking water around the world. His pioneering work in ion exchange science has also advanced technologies for desalination, wastewater reclamation, and carbon capture.

The Freese Award was established in 1975 and honors the legacy of Simon Wilke Freese, a civil engineer and ASCE Fellow whose career included designing more than 100 municipal water and sewer systems and over 200 dams and reservoirs. It is supported by Freese and Nichols, the engineering firm where Freese became a partner in 1927.

Each year, ASCE’s Environmental and Water Resources Institute selects an honoree based on a review of professional achievements and peer recommendations to receive the award and deliver the lecture. SenGupta was recognized with the Freese Award “for advancing and expanding the field of ion exchange science and technology, and for applying it to the development of sustainable technologies and new materials.”

He will present the Freese Lecture via video conference at 11:20 a.m. EDT on Wednesday, May 21, on the topic of “Development and Global Application of Hybrid Ion Exchange Processes in Sustainable Water Treatment: From Decontamination to Desalination,” as part of the 2025 World Environmental and Water Resources Congress (May 18-21, in Anchorage, Alaska).

In his lecture, SenGupta will highlight the development of innovative, sustainable water treatment technologies aimed at addressing global water scarcity. He will also discuss how hybrid ion exchange processes—now used worldwide—can transform wastewater into usable water and remove harmful contaminants, offering practical solutions for communities facing water challenges.

Read more about SenGupta’s research and accomplishments on his faculty profile.

Related Links

• Faculty Profile: Arup K. SenGupta

• ASCE Simon W. Freese Environmental Engineering Award and Lecture

• EWRI 2025 World Environmental and Water Resources Congress